Chapter 7: The Axial Skeleton Flashcards
What are the three components of the musculoskeletal system?
Bones, muscles, and joints
How many bones does the adult skeleton contain?
206
Why do infants/children have more bones?
They have some that fuse together later in life
The two principle divisions of the adult skeleton?
The axial skeleton - skulls bones, auditory ossicles, hyoid bone, ribs, sternum, bone of vertebral column
The appedicular skeleton- upper and lower limbs and bones that form girdles
How many bones in the axial skeleton?
80
How many bones in the appedicular skeleton?
126
5 main shapes of bones?
long, short, flat, irregular, and sesamoid
The bones have greater length than width and consist of a shaft and a variable number of epiphyses; are slightly curved for strength
Long Bones
These bones are somehwat cube-shaped, nearly equal in length and width; consist of spongy bone covered in a thin layer of compact bone tissue
Short bones
eg. wrist and ankle bones
These bones are generally thin and composed of two nearly parallel plates of compact bone tissue eclosing a layer of spongy bone tissue
Provide considerable protection and much surface area for for muscle attachment
Flat bones
eg cranial bones, sternum and ribs, scapulae
These bones have complex shapes and c annot be grouped into other categories; composition is variable;
Irregular bones
eg vertebrae, hip bones, certain facialbones, calcaneus
These bones develop in certain tendons where there is considerable friction, tension and physicial stress like palms and soles
Vary in number person to person
Not always ossified
Uusually only a few mm in diameter (except patellas)
Sesamoid Bones
eg. knee caps
These bones are small bones located in the joints between certain cranial bones
Sutural bones
Describe how raised surface markings are formed on bone
develop in response to certain forces like tension on a bone surface from tendons, ligaments, aponeuroses, and fascia - this tension causes ne bone to be deposited resulting in raised or roughened areas
How are bone surface depressions formed?
From compression on a bone surface
What are the two major types of surface markings
- depressions and openings
- Processes
Describe depressions/openings surface markings:
These allow the passage of soft tissues (eg blood vessels) or form joints
Describe processes (surface markings)
Projections or outgrowths that either help form joints or serve as attachment points for connective tissue ( ligaents and tendons eg)
List five depressions/openings categories
- Fissure
- Foramen
- Fossa
- Sulcus
- Meatus
This depression/opening is a narrow slit between adjacent parts of bones through which blood vessels or nerves pass
Fissure
eg. superior orbital fissue of sphenoid bone
This depression/opening is an opening through which blood vessels, nerves, or ligaments pass
Foramen
eg. optic foramen of sphenoid bone
This depression/opening is a shallow depression
Fossa
eg. coronoid fossa of humerus
This depression/opening is a furrow along bone surface that accomodates blood vessel, nerve or tendon
Sulcus
eg. intertubercular sulcus of humerus
This depression/opening is a tubelike opening
Meatus
eg. external auditory meatus of temporal bone
List of processes that form joints:
- condyle
- facet
- head
This process that forms a joint is a large, round protuberance with a smooth articular surface at the end of the bone
Condyle
eg. lateral condyle of femur
This process that forms a joint is smooth, flat, slightly concave or convex articular surface
Facet
eg superior articular facet of vertebra
This joint process is usually rounded, articular projection supported on a constricted portion (neck) of bone
Head
eg.head of femur
List the processes that form attachement points for connective tissues:
- Crest
- Epicondyle
- Line
- Spinous Process
- Trochanter
- Tubercle
- Tuberosity
This attachment point process is a prominent ridge or elongated projection
Crest
eg. iliac crest of hip bone
This attachment point process is typically a roughened projection above a condyle
epicondyle
eg. medial epicondyle of femur
This attachment point process is a long, narrow ridge or border (less prominent than crest)
Line
eg. linea aspera of femur
This attachment point process is a sharp, slender projection
Spinous process
eg. spinous process of vertebrae
This attachment point process is a very large projection
trochanter
eg. greater trochanter of femur
This attachment point process is a variably sized rounded projection
tubercle
eg. greater tubercle of humerus
This attachment point process is a variably sized projection that has a rough, bumpy surface
tuberasity
eg. ischial tuberosity of hip bone
This is the bony framework of the head, contains 22 bones, and rests on the superior end of the vertebral column
Skull
The two categories of skull bones:
Cranial Bones
Facial Bones
These skull bones form the cranial cavity and is made up of 8 bones
The cranial bones
These are the 8 cranial bones of the skull:
- Frontal Bone
- Two parietal Bones
- Two temporal bones
- the occipital bones
- the sphenoid bone
- Ethmoid bone
These skull bones form the face and consist of 14 bones
Facial Bones
These are the 14 bones of the face
- two nasal bones
- two maxillae
- two zygomatic bones
- the madible
- two lacrimal bones
- two palatine bones
- two inferior nasal conchae
- the vomer
Paranasal SInuses
caviities contained in the skull bone that are lined with mucous membranes and open into the nasal cavity
Middle ear cavities
Cavities in the temporal bones taht house the structures for hearing and equilibrium
What are the only movable bones of the skull?
ossicles and mandible
Function of the cranial bones
- protect brain
- stabilize the positions of the brain, blood vessels, lymphatic vessels and nerves through attachment of the inner surfaces to meninges
Outer surface has large surface area for attachment for muscles that move various parts of the head as well as muscles that produce facial expressions
framework of face and provides support for entrance to digestive and respiratory systems
This bone forms the forehead, the roofs of the orbits, and most of the anterior part of the cranial floor
Frontal bone
This is the flat part of the frontal bone that forms the forehead
frontal squama
This is th extruding upper ridge of the eye socket
Supraorbital Margin
This is a depression located near midline of the supraorbital margin_____________________; may be called this if incomplete_________________
supraorbital foramen
supraorbital notch
These two skulls cranial bones form the greater portion of the sides and rood of the cranial caviety
Parietal bones
These paired cranial bones form the inferior lateral aspects of the carnium and part of the cranial floor
Temporal Bones
The thin flat part of the temporal bone that forms the anterior and superior part of teh temple
temporal squama
This process projects from the inferior portion of the temporal squama and articulates with the temporal process zygomatic (cheek) bone
Zygomatic process
What two processes form the zygomatic arch?
the temporal process of the zygomatic bone and the zygomatic process of the temporal bone
The depression/socket located on the back, lower part of the zygomatic arch
mandibular fossa
The temperomandibular joint is made of the articulation of which surface markings combined with the mandible?
The mandibular fossa and articular tubercle
Back, lower portion of temporal bone, located behind/below the ear canal - and is filled with tiny air cells
mastoid portion of the temporal bone
Rounded projection of the temporal bone located behind the ear; attachment point for several neck muscles
mastoid process
The opening through which facial (VII) nerve and vestibulocochlear (VII) nerve pass
internal auditory meatus
triangular part of temporal bone, located at the floor of the cranial cavity between teh sphenoid and occipital bones, houses the internal ear and the carotid formamen
Petrous Portion of temporal bone
The cranial bone forms the posterior part and most of the base of the cranium
Occipital bone
The foramen or hole in the base of the occipital bone that the medulla oblongata connects with the spinal cord within
Foramen Magnum
Convex depressions on either side of the formamen magnum of the occipital bone that articulate with depressions on the first cervical vertabra to form the atlanto-occipital joint
Occipital condyles
External occipital protuberance
Middle part of the base of the skull, between all the other cranial bones; posterior and slightly superior to the nasal cavity and forms part of the floor, side walls and rear wall of the orbit; resembles a butterly with outstretched wings
sphenoid bone
This part of the sphenoid bone is the hollowed cubelike medial portion between the ethmoid and occipital bones
the body
term for the space inside the sphenoid bone body; this drains into the nasal cavity
sphenoidal sinus
Name the three parts of the sella turcica of the sphenoid bone
Horn saddle/anterior portion - tuberculum sallae
The seat saddle - Hypophyseal fossa
Posterior part/back of saddle - dorsum sellae (ridge)
This part of the sphenoid sella turcica is the saddle portion and houses the pituitary gland
hypopheseal fossa
what part of the sphenoid project laterally from the body and form the anterolateral floor of the cranium?
These also form part of the alteral wall of the skull just anterior to the temporal bone and can be viewed externally
the greater wings
These parts of the sphenoid bone are smaller than the greater wings and form a ridge of the floor of the cranium and the posterior part of the orbit of the eye
lesser wings
This is a delicate cranial bone that is located in the anterior part of the cranial floor, medial to the orbit and is spongelike appearance
Ethmoid bone
What are the four areas the ethmoid bone is part of
- part of anterior portion of the cranial floor
- the medial wall of the orbits
- the superior portion of the nasal septum
- most of the superior sidewalls of the nasal cavity
This part of the ethmoid bone lies in the anterior floor of the cranium and forms the roof of the nasal cavity ; contains olfactory formaen
cribriform plate
what are the 14 facial bones?
two nasal bones
two maxillas
two zygomatic bones
the mandible
two lacrimal bones
two palatine bones
two inferior nasal conchae
the vomer
Paired bone that are rougly the size and shape of a finger nail, smallest bones of the face, posterior and lateral to the nasal bones and form a part of the medial wall of each orbit
Contain the lacrimal fossa
Lacrimal bones
What is the lacrimal fossa?
a vertical tunnel formed with the maxilla that houses the lacrimal sac, where tears gather and pass into the nasal cavity
What are the two L-shaped bones that form the posterior portion of the hard palate, part of the floor and lateral wall of the nasal cavity and a small portion of the floors of the orbits?
The palentine bones
Describe the inferior nasal conchae (turbinates)
- inferior to the middle nasal conchae of the ethmoid bone
- scroll like
- form a part of the inferior lateral wall of the nasal cavity and project into the nasal cavity
- help swirl and warm and filter air
Which of the three turbinates contains the olfactory sensory receptors>
only the superior conchae which is part of the ethmoid bone
This facial bone is roughly triangular shaped and is found on the floor of the nasal cavity that articulates superiorly with the perpendicular plate of the ethomoid bone and sphenoid bone and inferiorly with the macillae and palatine bones along the midline
Forms the inferior portion of the bony nasal septum
The vomer
The upper jaw bone is made of these two bones paired
They articulate with every bone of the face expect the mandible
They form part of the floors of the orbits, part of the lateral walls and floor of the nasal cavity, and most of the hard palate
The maxillae
What is the hard palate?
The bony roof of the mouth
What bones forms the hard palate?
The horizontal plates of the palatine bones and the palatine processes of the maxillae
Cheek bones
zygomatic bones
What do zygomatic bones form?
the prominences of the cheeks and part of the lateral wall and floor of each orbit. Articulates with the frontal, maxilla, sphenoid and temporal bones
What makes the zygomatic arch?
The temporal process and ot he zygomatic bone and the zygomatic process of the temporal bone
What is the largest, strongest facial bone?
The Mandible
Describe the anatomy of the mandible
the body - a curved, horizontal portion
Rami - two perpendicular portions
What is the angle of the mandible?
the area where each rami meets the body of the mandible
What part of the ramus artibulates with the mandibular fossa and articular tubule of the temporal bone?
condylar processes
What three structures form the temporomandible joint?
Articulate tubercle of the temporal bone
mandibular fossa
condylar process of the mandible
What are the three structures that create the nasal septum?
perpendicular plate of the ethmoid bone; the vomer and the septal cartilage
Three cranial bones that help form the orbit?
The ethmoid, sphenoid and frontal bones
Four facial bones that help form the orbits?
The zygomatic, palatine, maxillae, and lacrimal bones
What are openings of the skull for blood vessels, nerces or ligaments?
foramen or foramina (plural)
Suture in adult
an immovable joint in that holds most skull bones together
Sutures in infant and children
movable and function as important growth centres in the developing skull
Usually sutures are named after what?
the bones they articulate
eg. sphenoparietal suture
frontozygomatic suture
Where is the coronal suture?
unites the frontal bone with both partietal bones
Where is the saggital suture?
unites the two parietal bones on the superior midline of the skull
Where is the lambdoid suture?
unites the two parietal bones to the occipital bone
which sutures might have sutural bones
the saggital and lambdoid suturesw
What suture unites the parietal and temporal bones on the lateral aspects of the skull
squamous sutures
Two periods of facial enlargment where sinuses increase in size
during the eruption of teeth
puberty onset
What function do the paranasal sinuses play in the weight of the skull
allow the skull to increase in size without changing in mass or weight
Which 4 skull bones contain paranasal sinuses?
Maxilla
Frontal
Ethmoid
Sphenoid
What bone does not articulate with other bones, is suspended from the styloid processes of the temporal bone, supports the tongue etc
hyoid bone
Anatomy of the hyoid bone
two lesser horns, two greatert horns, body
